1. Field of the Invention
The invention relates to a system wherein a phase fluctuation contained in a video signal is compensated to suppress the jitter of the video signal, and more particularly to a system for suppressing the jitter of a picture image being reproduced from a video signal which is read out from a rotatable or transportable recording medium recorded with the video signal such as a video tape recorder, video disc player or the like device.
2. Description of the Prior Art
Various systems have higherto been proposed which compensate phase flucturations contained in a signal read out from a video signal recording and reproducing device. In one typical type, a phase fluctuation of the horizontal synchronizing signal contained in the video signal is detected and a voltage controlled variable delay line is controlled by the detected signal so that the video signal passing through the voltage controlled variable delay line is so delayed as to cancel out the phase fluctuation In another type, a clock controlled analog memory is used and a video signal is passed therethrough so that the writing and reading speeds or timings for the video signal can be controlled by a clock frequency or writing and reading timing both corresponding to a phase fluctuation of the horizontal synchronizing signal. However, in order to obtain satisfactory performance with these conventional systems, the former required a greatly long delay line consisting of a lot of element and the latter a memory having a large storage capacity, along with many other circuit elements, resulting in high manufacturing cost preventing public recording and reproducing devices from being availed for practical use. A countermeasure for reducing the horizontal fluctuation associated with the reproduced picture image without using these expensive systems has also been proposed wherein a television receiver set for displaying a reproduced picture image is given ability for widening the amplitude and phase transmission characteristic against the fluctuation frequency associated with the input signal delivered to the horizontal AFC circuit incorporated in this television receiver set. This countermeasure, however, is incompatible with conditions for ensuring stability of the picture image against noises contained in the reception of broadcasting signals with the result that the television receiver set for displaying the reproduced signal of the recording and reproducing device needs to be added with function to change the characteristic of the horizontal AFC circuit. Further, the television receiver set with such additional characteristic change function is not popular and for this reason, the wide utilization of video players such as video tape recorders or video disc players is prevented.